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Push-me-pull-you shower install

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  • thfurnitureguy_4
    thfurnitureguy_4 Member Posts: 398
    Push-me-pull- you shower install

    Sorry not a heating question, Has anybody ever installed a 2 headed shower system? We have a big shower that needs a his an her shower heads. What kind of valve setup could work, or just install 2 supplies?
  • Constantin
    Constantin Member Posts: 3,796
    Do both of you like the same temperature?

    If so, you can buy a thermostatic valve that can pass the flow that you expect to get when both heads are on. It ought to allow "set and forget"... simply pipe the output to two 1/4 turn on-off valves and you should be good to go.

    A friend installed a double-shower in his house, and since he and his wife like to shower at different temperatures, they needed two temp-setting valves. The plumbers stated that having two thermostatic valves near to each other on the same supply could cause a problem, so one valve is thermostatic, the other is the regular kind.

    Have any of you experienced bad interaction between two thermostatic shower valves? Can someone explain why it's bad and what leads to the weird interaction?
  • ScottMP
    ScottMP Member Posts: 5,883
    Can not understand

    why having two thermostatic valves next to each other would be of any concern ??? I can not see how they would be effected by each other. Sounds like the plumber had his own agenda.

    You can each have a seperate mixing valve, thermostaic or otherwise, or one valve and volume controls that allow each shower head to operate individually.

    Scott

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  • hr
    hr Member Posts: 6,106
    As long as you

    can supply enough gpm for two heads from one mixer? Most single handle shower valves have fairly low flow these days. Some have the low gpm restriction built into the valve body instead of the shower head, these days.

    Might want to run 3/4" H&C to the valves(s)

    hot rod

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  • Dave Yates (PAH)
    Dave Yates (PAH) Member Posts: 2,162
    you need

    to start with the water distribution system to determine if you'll have adequate flow for both H&C delivery. Very few mfgrs have hi-flow faucets any longer and almost everything is rated for 2.5-GPM. A dual shower head take-off from a single faucet body will suffer. At a minimum, you'll want separate faucet bodies, which takes you right back to adequate delivery in the dist. system.

    Last, but hardly least, you'll need to consider bathing habits and the hot water source to see if you'll have the end results you desire. That's determined by adjusting the final delivery temp to suit, measuring the GPM flow rate, knowing the design temp of cold water being delivered and the storage temperature. Adjusted bathing temp minus the design temp is divided by the storage temp minus the design delivery temp to determine percentage of hot water in the shower stream. Once the GPM rate is known and the storage device capacity/efficiency/production/recovery can be determined, you'll know just how long you both can expect to remain under the cascading comfort.

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  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928


    Grohe thermostatic mixers allow high flow. ½" valve is more than adequate for two simultaneous regular flow shower heads. The ¾" valves can easily handle four or five.
  • Plumdog_2
    Plumdog_2 Member Posts: 873
    Look at Master Shower from Kohler

    You need 3/4 hot and cold supplies and then you pipe together a on-off-temperature valve and a shower head selector valve using a manifold type piping layout. You can use multiple overhead and multiple body type heads all from one control point. Follow the directions carefully.
  • thfurnitureguy_4
    thfurnitureguy_4 Member Posts: 398


    Thankyou all!
  • Tim_24
    Tim_24 Member Posts: 53
    Simplest

    way to go is simply install two , two handle shower only fixture sets. No need to monkey with manifolds and mixing vavles. 3/4 H & C with 1/2" branches to each side. Both sets have full, independent control.
  • thfurnitureguy_4
    thfurnitureguy_4 Member Posts: 398


    Nice!
  • ScottMP
    ScottMP Member Posts: 5,883
    Thats Great Tim

    That way both people could get scaulded when the dishwasher comes on.

    Better yet both people can fool around trying to maintane the temperature while showering.

    These valves are illigal in most parts of the country for a good reason.

    Scott

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  • thfurnitureguy_4
    thfurnitureguy_4 Member Posts: 398


    I was thinking that one head should be hot and the other cold, let um mix natural, like in the air.
  • Constantin
    Constantin Member Posts: 3,796
    Ahh, the memories...

    ... I once lived in a dorm with a group shower in the basement. One 10x10 room with 8 showers lining the room. No thermostatic, pressure-compensated, etc. valves to be found! Just you garden-variety gate valves...

    We all learned showering etiquette rather quickly, which is that anyone contemplating turning a valve announces it to the group first, so that everyone can step out of the flow, adjust the temperatures, and get back to cleaning themselves. I hear the dorm got renovated the year after I left. Oh well.
  • Tim_24
    Tim_24 Member Posts: 53
    Never

    had a problem in 8 years. IF the dishwasher is used while one shower head is going, slight change in temp only. If both are going, less of a temperature change. People, with the exception of the Rainman, have been able to manually control the supply of hot and cold water in sinks, showers and tubs, without scalding themselves since the invention of the automatic water heater. Some of the more challenged among us may have taken once to learn how it works. I find it neither unsafe nor particularly inconvenient to adjust a handle once or twice through the course of a shower. You mean to tell me that a basic, off-the-shelf, simple shower fixture with a handle for the cold water and another handle for the hot water is illegal? I don't believe it.
  • Dave Yates (PAH)
    Dave Yates (PAH) Member Posts: 2,162
    Not accurate Tim

    The reality is a stark contrast to your comments. In the US, there are thousands of scalding cases (derived from potable hot water systems) that seek out medical treatment each year, which tells me that's not all cases as many folks will self-medicate. Several dozen deaths too, but for those who survive third-degree scalds, skin grafts are needed. If that's a child, the skin grafts do not grow & must be periodically replaced. That's a lifetime of disability and a childhood filled with misery.

    The so-called mantra that 120 F water is a "safe" storage temp, is little more than a pipe dream too. Third degree scalds can still occur and do. Elderly and infants suffer first as their skin is very thin, which renders them 4X's more susceptable to scalding that a healthy young adult. As we age, we lose sensitivity to scalding temps and those with med conditions may not be able to discern scalding temps.

    Existing regs governing residential water heaters allow for something called stacking to occur - even with the thermostat or aquastat set for 120 F. Stacking can cause extremely hot water to build in layers in any storage vessel. Regs permit that to be as high as 190 F & still be in compliance.

    Personally, I think anybody advocating a bathing environment faucet that's NOT ASSE 1016-certified as a scald-guard device needs a check up from the neck up. There are three types: P (pressure balance), which is blind to seasonal temperature changes & don't get my vote; T (temperature reacting), which are better but still fall short for sudden pressure changes; and PT, which combine both safety features and should be mandated for all bathing environments - period. My parents have PT in all their bathing modules. I'd be remiss if I let them utilize a non-protected faucet. Most codes call for ASSE 1016 valves in bathing areas. That's a certified valve, not one that simply claims it meets ASSE 1016.

    Obviously, anyone who does their own work can install anything they like. Suit yourself Tim, but don't be giving out potentially dangerous advice to others without doing some research on the facts first.

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  • Plumdog_2
    Plumdog_2 Member Posts: 873
    What Dave said

    I knew a guy that got scalded in a motel shower and jumped out thru the glass; which was not tempered. He bled to death. This is no lie; nor is it a joke.
  • ScottMP
    ScottMP Member Posts: 5,883
    My understanding

    was that one of the driving reasons for anti-scauld regulations was to eliminate injuries from people jumping out of the way of scaulding water.

    By the way ...

    Massachusetts Plumbing Code , 248 CMR, 2:10 (e) : "The water supply to said shower head shall be supplied through an approved individual single handle thermostatic and/or preasure balancing device. "

    There is a reason for these codes.

    Scott

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  • Dave Yates (PAH)
    Dave Yates (PAH) Member Posts: 2,162
    falling while bathing

    Another reason: when slipping or falling, the one thing people will reach for without thinking is the faucet handle(s) because that's the one item they've been reaching for over many years. Many scalding cases have occurred as folks fell or slipped and inadvertently turned the temperature up. In one old gents case, he couldn't get back up. By the time they found him, his skin had been burned to a point where much of it simply peeled away. The loose skin then clogged the grid strainer, raised the water level and he drowned. Just one of many gruesome true stories uncovered while doing research for the Watts video on scalding.

    A free copy is available by visiting Wattsreg.com and clicking on the "Scalding: Danger Lurks" link on their home page. I would encourage Tim and anyone else who desires an educational introduction to the issues regarding hot water safety to get a copy of this DVD. It's free. Excerpts from the Watts video "Explosion: Danger Lurks" are included during the intro. Lots of people thought the extra cost for a T&P relief valve, instead of just the pressure relief valves, was something not needed - just as many ill-informed folks think certified ASSE 1016 valves aren't necessary and that they cost too much & that's why I elected to build the old footage into the video. Besides which, it's a hoot to watch guys running around in pith helmets while blowing up water heaters. Fair warning: there is a brief clip showing a young lad who suffered third-degree burns & it's not pretty.




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  • Larry Weingarten
    Larry Weingarten Member Posts: 3,616
    Another way...

    ... to get decent flow from a modern tub/shower valve is to plug the shower outlet and use the tub outlet. "T" from there for your two shower heads. The tub outlet provides much better flow.

    Yours, Larry
  • Tim_24
    Tim_24 Member Posts: 53
    I learned something

    new here. We have tried to legislate safety, and in this case, for a good reason. Just one less way for people to hurt themselves, though the determined will find other ways, no doubt. I don't dispute that you guys are correct and that I am wrong, though I still have trouble believing normal people regularly injury themselves so carelessly. Keep these people away from the kitchen!
  • Dave Yates (PAH)
    Dave Yates (PAH) Member Posts: 2,162
    not their fault

    Tim,

    Getting scald burns doesn't imply carelessness on anyone's part and is often caused by something beyond their control. Infants can obviously feel the pain, but sometimes not realize its source and, therefore, can't determine how to get out of harm's way.

    Sudden pressure imbalances can occur, obviously much more pronounced than the imbalance you have in your home, which can (and does) see a sudden deluge of scalding hot water.

    Elderly and infirm folks are less sensitive to water temperatures and often don't realize they're being exposed to scalding temps.

    All of this info (and more) is in the DVD @ wattsreg.com

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  • bovide_4
    bovide_4 Member Posts: 161
    all's you need

    is a Grohe or Kohler 3/4" mixing valve, and a pair of 3/4" or 1/2" volume controls. Pipe the risers to the mixing valve. From the mixing valve pipe to the volume controls. From the volume controls pipe to the shower heads.
    This is the simplest way to go, and includes scald protection. Be careful with the rough-in depth, as the tolerances are tight.
  • Dirk Wright
    Dirk Wright Member Posts: 142
    Turn down HWH?

    Why can't you just turn the HWH down to 110 or 100? this is easy to do, particularly on a tankless model. On the other hand, won't this low temperature mean that the dishwasher won't get the dishes as clean and/or sterile?
  • Dave Yates (PAH)
    Dave Yates (PAH) Member Posts: 2,162
    bacterial issues

    legionella, in particular and stacking of layers of hot water.

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  • Supply House Rick
    Supply House Rick Member Posts: 1,399
    Your DVD

    Dave,
    I have your DVD. I think it's a valuable tool for the people I sell to. It helps them understand the dangers of scalding and the value of mixing valves. Everbody out there should get it and pay attention...
    Thank Dave,

    Rick
  • Dave Yates (PAH)
    Dave Yates (PAH) Member Posts: 2,162
  • ScottMP
    ScottMP Member Posts: 5,883
    Tim

    Good to see you have an open mind. We all learn stuff, thats why I come here.

    Have a great weekend.

    Scott

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  • Dirk Wright
    Dirk Wright Member Posts: 142
    what about tankless?

    Is bacteria an issue with tankless water heaters if their thermostat is turned down below 130F? My tankless has a 5 gal heat exchanger. I currently have it set at 130, but I can easily turn it down.
  • Dave Palmer_3
    Dave Palmer_3 Member Posts: 388
    sounds

    like prison :P lol,if it was my luck it would be co-ed now too,Dave
  • Dave Yates (PAH)
    Dave Yates (PAH) Member Posts: 2,162
    great question!

    You are correct that tankless water heaters do not offer bacteria the same opportunities for shelter and reproduction, which is why tank-style water heaters or hot water storage vessels are frequently included in lists identifying "amplifiers" - suitable host sites for bacterial amplification.

    However, while tank-style water heaters are often mentioned, it's widely misunderstood the the hot water system in a home consists of three distinct components: point of source (the storage vessel); distribution system (anything transporting water from storage to part three); points of use, which includes all distal sites where water comes into direct contact with people, but also, an open direct hydronic use where water can more easily see blooms of bacteria as it sits stagnant in long horizontal runs of tubing with the pH,temperatures and food (biofilms) - all of the criteria needed for rampant amplification.

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  • singh
    singh Member Posts: 866
    Mr. Yates

    I have always believed, and still do think that
    water heaters should be used only to heat water, not kill bugs.
    I advocate use of frequent chlorination or UV systems for that.
    And water heaters set to 120* to limit scalding issues.

    Why are'nt more plumbers and code officials insisting on other devices
    and means to control legionella and other nasties, why do we think the
    easiest solution is to raise water heater temps and throw on a themostatic mixing valve?

    Not to mention the extra energy costs to heat at higher temps then lower thru mixing valve and then again thru shower valve. Sorry I don't see the logic.

    Anyway seems like a catch 22 anyway for contractors and liabilty concerns.
    Bugs or burns.

    PS. Hope all is well, hope to see you again real soon.
  • Dave Yates (PAH)
    Dave Yates (PAH) Member Posts: 2,162
    also a very good question

    Chlorination, even hyper-chlorination, of potable water systems does not effectively kill off legionella bacteria. Also, chlorine dissipates as water is heated, which accounts for the deterioration and pitting seen in hot vs. cold water lines. We currently see between 2 and 4 PPM chlorine in municipal systems. If chlorine is to be utilized to kill Legionella, the concentration must be 2,000 times greater to penetrate biofilms. Organics will become carcinogenic and anything metallic or (most) plastics will be rapidly compromised.

    Storing water at higher temperatures costs a minimal amount. (There are several articles in my archives at contractormag.com on this subject.) Hot water pasteurization is the most effective method available for homes and the scald-guard devices should be installed anyway - no matter what temp is utilized for storage.

    UV systems are quite good IF the bugs can be seen and the flow rate is within the UV's range for altering the DNA to render them sterile. Legionella have an interesting habit of utilizing exoskeletons of bugs they consume as a Trojan Horse nursery until they finally burst forth once the nursery is so full it can't contain their expanding numbers. Global Pipe from Germany was kind enough to furnish the only live micron-microscope images of this happening, which is included in the DVD. In order for UV to be truly affective in granting a 100% sterilization rate, ultrasonic bombardment is utilized upstream to break up any cysts or exoskeletons so that the bugs are "naked" while passing by the UV rays.

    A much better method for actually killing off the bugs, is chlorine dioxide (which does penetrate biofilms) and, even better that that, copper silver ionization, which has a residual kill-rate, penetrates biofilms & is the best method for large systems (like hospitals) where long lengths of potable piping may remain stagnant for long periods. Both of which are too expensive for residential use (at this time), which leaves us with hot water as the most affective if it is maintained above 133 F. At 140 F, a contact time of 20-minutes is still required to diminish the numbers of legionella. Danfoss performed a study to determine why super-heated flushes of water only offers a temporary reduction in legionella bacteria counts and found they survive 180-F flushes in the outer fringes of the biofilms.

    That's why we must view this as a system-wide treatment, rather than just treating one component - the point of source. Maintaining the storage temp at 140 min (as CIPH has adopted in their codes), adding recirc at 133 min in the dist system and adding ASSE 1016 TP valves for bathers and ASSE 1016 T valves at all other points of use will provide the final reduction to 120, 110 or whatever temp you desire. And that is the only manner in which you can currently protect a residential potable hot water system that's very effective and doesn't break the bank.

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  • singh
    singh Member Posts: 866
    Biofilm, exoskeletons and bugs oh my!

    I'm going to have to get this DVD.
    I'm just a "mere" plumber, but this topic intrigues me.
    Who would have thunk us plumbers would need to know this stuff.
    Thanks for the good explanation.
  • Dave Yates (PAH)
    Dave Yates (PAH) Member Posts: 2,162
    simply because

    we plumbers are responsible for saving more lives than all of the doctors and medical advances combined throughout all of recorded history!

    Google typhoid, cholera and dysentery to see just how dramatic a change sanitary plumbing made in the health of folks. Makes the current panic items, like Lyme or West Nile Virus look like child's play. Imagine 5,000 people dying a horrible death - in just two weeks - in just one of our major cities. Then multiply that by lots of major cities. All within the same time frame. It's been just under 100 years since the world has seen a great pandemic sweep from Asiatic regions up through Europe and then to our country. That's what has everyone so panicked by the bird flue. In researching world pandemics and epidemics for an RPA convention presentation a few years ago, I was shocked to find almost every single major world-wide pandemic episode emanated from the very same region. Same one where the bird flue is seeing its start.


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